Multi-component integrated circuit contacts

ABSTRACT

An integrated circuit connection is describe that includes a first, securing member and a second, connection member. The first member, in an embodiment, is a spike that has a portion of its body fixed in a layer of an integrated circuit structure and extends outwardly from the integrated circuit structure. The second material is adapted to form a mechanical connection to a further electrical device. The second material (e.g., solder), is held by the first member to the integrated circuit structure. The first member increases the strength of the connection and assists in controlling the collapse of second member to form the mechanical connection to another circuit. The connection is formed by coating the integrated circuit structure with a patterned resist and etching the layer beneath the resist. A first member material (e.g., metal) is deposited. The resist is removed. The collapsible material is fixed to the first member.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. Application Ser. No.12/766,381, filed Apr. 23, 2010, which is a divisional of Ser. No.11/535,414, filed Sep. 26, 2006, which is a Continuation of U.S.application Ser. No. 10/231,877, filed Aug. 29, 2002, now issued as U.S.Pat. No. 7,115,998, which these applications are incorporated herein byreference in their entirety.

TECHNICAL FIELD

The present invention relates generally to integrated circuit contacts,and in particular to contact structures and methods for fabricating thecontacts.

BACKGROUND

Wafers are fabricated with a plurality of dies each having a pluralityof integrated circuit elements therein. A die represents one individualchip that must be separated from adjacent dies before packaging.Contacts are added to the die before packaging the chip. One type ofcontact is a solder ball. Solder balls are used to mount the integratedcircuit chip to a substrate. In today's technological environment, thereis a continuous desire to increase integration of greater numbers ofcircuits onto a single semiconductor chip. At the same time there is arequirement to increase performance of the chip, whether it is a memorychip, processor chip, telecommunication chip or other integrated circuitchip. As more functions are integrated into a chip, the number ofinterconnections to other chips and/or electrical devices increases.Often, the goal is to provide the chip with as many input/output (“I/O”)contacts or terminals as possible. Accordingly, the solder bumps aremanufactured as small as possible to increase the number of solderbumps. However, decreasing the size of the solder bumps decreases theirstrength, for example, shear strength. Such solder bumps are more likelyto fail. This may decapitate the chip.

For the reasons stated above, for other reasons stated below, and forother reasons which will become apparent to those skilled in the artupon reading and understanding the present specification, there is aneed in the art for improved integrated circuit contacts or terminals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary cross-sectional view of a substrate structureduring a fabrication step according to the present invention.

FIG. 2 is a fragmentary cross-sectional view of a substrate structureduring a subsequent fabrication step according to the present invention.

FIG. 3 is a fragmentary cross-sectional view of a substrate structureduring a subsequent fabrication step according to the present invention.

FIG. 4A is a fragmentary cross-sectional view of a substrate structureduring a subsequent fabrication step according to an embodiment of thepresent invention.

FIG. 4B is a fragmentary cross-sectional view of a substrate structureduring a subsequent fabrication step according to another embodiment ofthe present invention.

FIG. 5A is a fragmentary cross-sectional view of a substrate structureduring a subsequent fabrication step according to an embodiment of thepresent invention.

FIG. 5B is a fragmentary cross-sectional view of a substrate structureduring a subsequent fabrication step according to another embodiment ofthe present invention.

FIG. 6 is a fragmentary cross-sectional view of a substrate structureduring a subsequent fabrication step according to the present invention.

FIG. 7A is a fragmentary cross-sectional view of a substrate structureaccording to an embodiment of the present invention.

FIG. 7B is a fragmentary cross-sectional view of a substrate structureaccording to an embodiment of the present invention.

FIG. 8 is a fragmentary cross-sectional view of a substrate structureaccording to an embodiment of the present invention.

FIG. 9 is a fragmentary cross-sectional view of a substrate structureaccording to an embodiment of the present invention.

FIG. 10 is a fragmentary cross-sectional view of a substrate structureaccording to an embodiment of the present invention.

FIG. 11 is an elevational view of a substrate structure according to anembodiment of the present invention.

FIG. 12 is an elevational view of the FIG. 11 substrate structure duringa fabrication step according the present invention.

FIG. 13 is an elevational view of the FIG. 11 substrate structure duringa subsequent fabrication step according the present invention.

FIG. 14 is an elevational view of the FIG. 11 substrate structure duringa subsequent fabrication step according the present invention.

FIG. 15 is an elevational view of the FIG. 11 substrate structure duringa subsequent fabrication step according the present invention.

FIG. 16 is an elevational view of the FIG. 11 substrate structure duringfabrication according the present invention.

FIG. 17 is an elevational view of the FIG. 11 substrate structure duringfabrication according the present invention.

FIG. 18 is an elevational view of the FIG. 11 substrate structure duringfabrication according the present invention.

FIG. 19A shows an assembly according to the present invention.

FIG. 19B shows another assembly according to the present invention.

FIG. 20 is a flow chart of a method according to the present invention.

FIG. 21 is a fragmentary cross-sectional view of a substrate structureaccording to an embodiment of the present invention.

DETAILED DESCRIPTION

In the following detailed description of the embodiments, reference ismade to the accompanying drawings which form a part hereof, and in whichis shown by way of illustration specific embodiments in which theinventions may be practiced. These embodiments are described insufficient detail to enable those skilled in the art to practice theinvention, and it is to be understood that other embodiments may beutilized and that process, electrical or mechanical changes may be madewithout departing from the scope of the present invention. The termswafer and substrate used in the following description include any basesemiconductor structure. Both are to be understood as includingsilicon-on-sapphire (SOS) technology, silicon-on-insulator (SOI)technology, thin film transistor (TFT) technology, doped and undopedsemiconductors, epitaxial layers of a silicon supported by a basesemiconductor structure, as well as other semiconductor structures wellknown to one skilled in the art. The following detailed description is,therefore, not to be taken in a limiting sense, and the scope of thepresent invention is defined only by the appended claims and theirequivalents.

It is noted that for purposes of interpreting this disclosure and theclaims that follow, the special reference terms “on”, “over”, “above”,“beneath” and the like are utilized to describe relative orientations ofvarious elements to one another. The terms are not utilized in anabsolute and global sense relative to any external reference.Accordingly, a first material recited as being “beneath” a secondmaterial defines a reference of the two materials to one another, butdoes not mean that the first material would actually be “under” thesecond material relative to any reference external of the two materials.

FIG. 1 shows a substrate assembly 10 that includes an integrated circuitlayer 12. In an embodiment, the integrated circuit layer 12 is a die. Inan embodiment, the integrated circuit layer 12 includes a semiconductorwafer. In an embodiment, the integrated circuit layer 12 is a substrate.Integrated circuit layer 12 includes an integrated circuit connected toa conductive bond pad 14. In an embodiment, the bond pad 14 includes ametal. It will be understood that substrate assembly 10 is simplified tobetter illustrate the present invention. For example, only one bond pad14 is shown, however, an integrated circuit typically has a plurality ofbond pads to provide I/O terminals.

The integrated circuit layer 12, in an embodiment, includes anintegrated circuit memory device. In an embodiment, the memory deviceincludes address and data interconnects that are connected to bond pads,such as bond pad 14. The memory device, in an embodiment, includes adynamic random access memory (DRAM). In other embodiments, the memorycircuit includes at least one of SRAM (Static Random Access Memory) orFlash memories. Additionally, the DRAM could be a synchronous memorydevice such as SGRAM (Synchronous Graphics Random Access Memory), SDRAM(Synchronous Dynamic Random Access Memory), SDRAM II, and DDR SDRAM(Double Data Rate SDRAM), as well as Synchlink or Rambus DRAMs and otheremerging memory technologies as known in the art. The integrated circuitlayer 12, in an embodiment, includes logic circuits. In an embodiment,the logic circuits are address decoders. In an embodiment, the logiccircuits are data processing circuits. In an embodiment, the logiccircuits include microprocessors. It will be further recognized that theintegrated circuit layer 12, in an embodiment, includes both logiccircuits and memory circuits. In an embodiment, the integrated circuitlayer includes a system-on-a-chip. It will be recognized that thepresent invention is applicable to any electronic device that ismechanically or electrically connectable to another pad.

An insulating layer 16 is formed on the upper surface of the integratedcircuit layer 12. The insulating layer 16 includes an aperture open tobond pad 14. In an embodiment, the insulating layer 16 covers the entireintegrated circuit layer 12 except over bond pad 14. That is, theinsulating layer 16 does not cover the bond pad 14. In an embodiment,the insulating layer 16 is a passivation layer that essentially enclosesthe integrated circuit layer 12. In an embodiment, the insulating layer16 is a passivation layer that essentially covers the top surface of theintegrated circuit layer 12. In an embodiment, insulating layer 16includes a glass material. In an embodiment, insulating layer 16includes inorganic polymers. In an embodiment, insulating layer 16includes benzocyclobutenes (BCB). In an embodiment, insulating layer 16includes polymides (PI). In an embodiment, insulting layer 16 includesat least one of silicon dioxide, silicon nitride, or silicon oxynitride.In an embodiment, insulating layer 16 includes organic polymers.

A redistribution level 18 is formed on insulating layer 16.Redistribution level 18 is adapted to provide an electrical connectionfrom the bond pad 14 to an external electrical circuit. Redistributionlevel 18 provides the electrical connections spaced outwardly from bondpads in an embodiment. Redistribution level 18 includes a furtherinsulating layer 21 formed on insulating layer 16. Insulating layer 21includes, in an embodiment, a dielectric material. In an embodiment,insulating layer 21 includes inorganic polymers. In an embodiment,insulating layer 21 includes benzocyclobutenes (BCB). In an embodiment,insulating layer 21 includes polymides (PI). In an embodiment,insulating layer 21 includes poly benzobisoxazole (PBO). In anembodiment, insulating layer 21 includes organic polymers. Theinsulating layer 21 is patterned to form a recess that receives aconductive trace 23. Trace 23 is connected to and extends outwardly,away from bond pad 14. In an embodiment, conductive trace 23 isdeposited on top of insulating layer 21. For example, a lift off processis used to fabricate trace 23. A liftoff layer is formed in a pattern oninsulating layer 21 to cover portions of insulating layer 21 and exposeportions of insulating layer 21. The conductive trace 23 is deposited asa layer on the liftoff layer and the exposed portions of insulatinglayer 21. The liftoff layer is stripped away along with the portion ofthe conductive trace layer on the liftoff layer. The portion of theconductive trace layer on insulating layer 21 remains to form trace 23.In another example, a seed layer is deposited on the portions of theinsulating layer where the trace 23 will be formed. The material of thetrace is deposited on, e.g., grows only on, the seed layer to form thetrace 23. In an embodiment, a layer of metal to form the trace 23 isdeposited to substantially cover layer 21. A resist layer is formed onthe metal layer. The resist is patterned so that the area of the metallayer that will form the trace is covered by the resist. The exposedarea of the metal layer is etched. The resist layer is removed, e.g.,dissolved. The trace 23 remains. It will also be appreciated that thetrace, in embodiments, is formed by a damascene process orchemical-mechanical polishing process. In an embodiment, conductivetrace 23 includes a metal. In an embodiment, the conductive traceincludes copper. In an embodiment, the conductive trace includesaluminum. In an embodiment, the conductive trace includes a titaniumcoating on top of the aluminum. In an embodiment, the conductive traceincludes an elongate aluminum body 23A with end caps 23B and 23C atrespective ends of the body. One of the caps 23B directly contacts bondpad 14. The other cap 23C is at the other end of the body 23A.Redistribution level 18 further includes a further insulating layer 25on conductive trace 23 and insulating layer 21. In an embodiment,insulating layer 25 completely covers the top surface of the conductivetrace 23 and insulating layer 21. In an embodiment, insulating layer 25includes inorganic polymers. In an embodiment, insulating layer 25includes benzocyclobutenes (BCB). In an embodiment, insulating layer 25includes polymides (PI). In an embodiment, insulating layer 25 includespoly benzobisoxazole (PBO). In an embodiment, insulating layer 25includes organic polymers. The layers 12, 14, 16, 21, 23, and 25 form apackaged integrated circuit device or structure.

FIG. 2 shows a further fabrication step according to the presentinvention. A resist layer 27 is deposited on upper insulating layer 25.Resist layer 27 is patterned to include an aperture 29 through resistlayer 27 to insulating layer 25. In an embodiment, the aperture 29 isdirectly above the trace 23. In an embodiment, aperture 29 is verticallyaligned with or directly above the cap 23C that is remote from bond pad14. A via 31 in the upper insulating layer 25 is formed verticallyaligned with the resist aperture 29 (FIG. 3). In an embodiment, anetchant, which is resisted by resist layer 27 and which removesinsulating layer 25, forms via 31. The trace 23 acts as an etch stop ofthe etchant. Via 31 extends through insulating layer 25 to trace 23 andis vertically aligned with aperture 29.

In the embodiment with the trace 23 including a coating of titanium, thetitanium is removed. This procedure does not require extra masking stepsas the titanium is removed through resist aperture 29 and via 31. In anembodiment, the titanium is etched. In an embodiment, a plasma etch isused to remove the titanium. In an embodiment, a zincate bath is used toremove the titanium. The underlying aluminum portion of the trace is nowexposed through aperture 29 and via 31. This removes the titanium, whichis not does not bond well to nickel, and exposes the aluminum, whichbonds catalytically with the nickel. In an embodiment, nickel is used toform a component of the connection as explained herein.

FIG. 4A shows a further fabrication step of an embodiment of the presentinvention. An integrated circuit, connection component 35A of theconnection of the present invention is formed in the resist aperture 29and insulating layer via 31. Integrated circuit component 35A extendsfrom the top surface of resist layer 27 through insulating layer 25.Component 35A has a height that is greater than the thickness ofinsulating layer 25. Thus, component 35A has an upper end that is abovethe upper surface of layer 25. In an embodiment, component 35A extendsat least partially through the resist layer 27. In an embodiment,component 35A extends essentially to the upper surface of the resistlayer 27 such that its upper end is essentially co-planar with the uppersurface of the resist layer 27. Component 35A, at a lower end, directlycontacts trace 23. In an embodiment, component 35 contacts trace cap23C. In an embodiment, component 35A is formed by a metal platingprocess. In an embodiment, component 35A is a metal. In an embodiment,component 35A includes nickel. In an embodiment, component 35A isessentially pure nickel. Nickel is suited for the connection componentas it as sufficient strength and fabrication characteristics. Nickelprovides an improved shear strength to an integrated circuit connection.Further, nickel is malleable which allows the component 35A to berepeated stressed without failing. In an embodiment, the aluminum traceis activated in a zincate bath. This allows the nickel to catalyticallybond to the aluminum trace. Further, this does not require anelectrolytic fabrication process. In an embodiment, component 35Aincludes copper. In an embodiment, component 35A includes non-metalconductors. After the component 35A is formed, the resist layer 27 isremoved or stripped (FIG. 5A).

Component 35A has an elongate body 37 with a lower end directlycontacting trace 23 and an upper end positioned above the insulatinglayer 25. In an embodiment, the upper end of body 37 is positioned atthe upper surface of the resist layer 27. The upper end of body 37 isspaced upwardly from the top surface of layer 25. In an embodiment, body37 is malleable. The component body 37 includes a first body portion 37Athat is free standing and connected to a second body portion 37B. Thesecond body portion 37B is fixed in aperture 31 of the insulating layer25. Stated another way, the first body portion 37A is cantilevered fromthe second body portion 37B and layer 25. In an embodiment, component35A has an essentially right parallelepiped or right cylindrical shapein embodiments of the present invention. In an embodiment, the component35A has a height greater than or equal to about 32 microns. In anembodiment, the component 35A has a height greater than 50 microns. Inan embodiment, component 35A has a height in the range of about 100 toabout 500 microns. It will be appreciated that the component 35A isscalable dependent on the application.

FIG. 4B shows another embodiment of the present invention that issimilar to the embodiment shown in FIG. 4A except the connectioncomponent 35B extends through both the resist layer 27 and insulatinglayer 25. The formation process continues so that component 35B includesa head 39 formed on the upper surface of resist layer 27. Connection 35Bhas a generally pin, spike or nail shape (FIG. 5B). Component 35B has anelongate body 37 with a lower end directly contacting trace 23 and anupper end connected to a head 39. In an embodiment, the body 37 ismalleable. The component body 37 includes a first body portion 37A thatis free standing and connected to a second body portion 37B. The secondbody portion 37B is fixed in aperture 31 of the insulating layer 25.Stated another way, the first body portion 37A is cantilevered from thesecond body portion 37B and layer 25. The head 39 includes conductingmaterial that was deposited on the upper surface of resist layer 27 whenthe connection component 35 was formed. The resist layer 27 is stripped(FIG. 5B). Head 39 is spaced upwardly from the top surface of layer 25.As a result, component 35 has an essentially nail or spike shape in anembodiment of the present invention. The head 39 has a first dimensionthat is greater than the width of the body 37. The head 39 extendsradially outwardly from the center axis of the body 37. In anembodiment, the component body 37 has a width of about 5 microns. Thehead 39 has a width in a range of about 6 microns to about 10 microns.In an embodiment, the component 35B has a height greater than 50microns. In an embodiment, component 35B has a height in the range ofabout 100 to about 500 microns. It will be appreciated that thecomponent 35B is scalable dependent on the application.

FIG. 6 shows a further fabrication step of an embodiment of the presentinvention. A contact forming material 40 is placed on the layer 25 overthe component 35B to form a contact assembly 41B. Contact formingmaterial 40 is a further component of the contact of the presentinvention. Component 35B buried within material 40. It will beappreciated that other forms of the first component, such as components35A and 35C-35E, as described herein could be used with material 40. Inan embodiment, the contact material 40 include a solder paste. In anembodiment, the solder paste includes controlled-collapse chipconnection (C-4) materials. In an embodiment, the solder paste includestin and lead (Sn and Pb). In an embodiment, the solder paste includes aneutectic material. Contact material 40 is deposited in a nonuniformshape. Contact assembly 41B is heated to reflow the contact material 40to form a contact ball 42 at each location defined by at least onecomponent 35 (FIG. 7B). The component 35B remains buried within thecontact ball 42. Component 35B extends radially inwardly into thecontact ball 42. Component 35B extends into the solder ball less thanhalf the diameter of the solder ball 42. In an embodiment, component 35Bextends into the solder ball 42 less than one-third the diameter of thesolder ball 42. In an embodiment, component 35B extends into the solderball 42 about 25% of the diameter of the solder ball 42. In anembodiment, the component has a height above layer 25 of about 5microns. In an embodiment, the solder ball has a height or diameter ofabout 25 microns. This allows solder ball 42 room to collapse and nothave the other contact abut the component 35B. In an embodiment,component 35B is adapted to assist in control the collapse of ball 42Bduring its joining to the other contact (not shown). In an embodiment,the connection assembly 41B has a diameter of less than 100 microns(:m). In an embodiment, the connection assembly 41B has a diameter ofless than 90 microns (:m). In an embodiment, the ball 42B has a diameterthat is greater than the height of portion of the component 35Bextending above the upper surface. In an embodiment, the ball 42B has aradius that is greater than the height of portion of the component 35Bextending above the upper surface. In an embodiment, the ball 42B has adiameter that is less than the height of portion of the component 35Bextending above the upper surface. In an embodiment, the ball 42B has aradius that is less than the height of portion of the component 35Bextending above the upper surface.

FIG. 7A shows an embodiment of a contact assembly 41A of the presentinvention. Assembly 41A includes component 35A with a collapsiblecomponent 43. Collapsible component 43 is placed on the free end ofcomponent 35A remote from the upper surface of insulating layer 25. Thatis, collapsible component 43 does not contact the below integratedcircuit assembly. The collapsible component 43 has a dimension that isless than the height of the portion of the component 35A above theintegrated circuit assembly. In an embodiment, the dimension isdiameter. In an embodiment, the dimension is radius. In an embodiment,the dimension is height. In an embodiment, the dimension is width. In anembodiment, collapsible component 43 includes a solder. In anembodiment, collapsible component includes tin and lead (Sn and Pb). Inan embodiment for forming the collapsible component 43 on component 35A,the resist layer 27 is left on layer 25 until the collapsible material43 is adhered to the end of the component 35A. Thereafter, the resistlayer 27 is stripped from the IC structure. In an embodiment, only thefree end of the component 35A is dipped into a collapsible materialbath.

FIG. 8 shows an embodiment of the connection according to the presentinvention. Generally similar elements in the drawing figures have thesame reference numbers as previously recited. Component 35C is similarto the component described above except it includes a base 45 buriedwithin the integrated circuit assembly. In an embodiment, base 45 ispositioned at the lower end of the component body 37. In an embodiment,base 45 is generally beneath layer 25. Base 45 is formed on theconductive trace 23. In an embodiment, the insulating layer 25 is formedafter the base 45 is deposited on trace 23. In an embodiment, base 45includes a metal. In an embodiment, base 45 includes nickel. Base 45includes a dimension that is greater than a corresponding dimension ofthe component body 37. In an embodiment, the dimension of the base 45that is greater is its width and/or diameter. In an embodiment, base 45includes a dimension that is greater than a corresponding dimension ofthe component head 39. In an embodiment, the dimension of the base 45that is greater is its width and/or diameter. Base 45 is adapted to actas an anchor to secure the component 35 and component ball 42 to thedevice assembly 10. The base 45 is formed, in an embodiment, by placinga sacrificial layer on layer 21 and trace 23. The sacrificial layer ispatterned with an aperture for the base. The material of the base, i.e.,a conductor, is deposited in at least the sacrificial layer aperture toform the base. The sacrificial layer and any of the base material on thesacrificial layer is stripped off layer 21 and trace 23. Thereafter, theconnection component 35C is formed as described herein. While FIG. 8shows component 35C as having a head 39, it is within the scope of thepresent invention to form the FIG. 8 embodiments without head 39.

FIG. 9 shows an embodiment of the connection according to the presentinvention. Component 35D includes a stud 50 connected to the lower endof the upper portion 37A of component body 37. The stud 50 extendsthrough layer 25 with a body 51 in layer 25 and a cap 53 above layer 25.In an embodiment, the stud 50 has an upper surface essentially co-planarwith the upper surface of layer 25. In an embodiment, stud 50 includesan upper surface below upper surface of layer 25. In an embodiment, thestud body 51 includes a dimension that is greater than a correspondingdimension of the component body 37A, which extends upwardly from studbody 51. In an embodiment, the dimension of the body 51 that is greateris its width and/or diameter. In an embodiment, body 51 includes adimension that is greater than a corresponding dimension of thecomponent head 39. In an embodiment, the dimension of the body 51 thatis greater is its width and/or diameter. Body 51 is adapted to act as ananchor to secure the component to the device assembly 10. In anembodiment, the stud cap 53 includes a dimension that is greater than acorresponding dimension of the component body 37A. In an embodiment, thedimension of cap 53 that is greater is its width and/or diameter. In anembodiment, cap 53 includes a dimension that is greater than acorresponding dimension of the component head 39. In an embodiment, thedimension of the cap 53 that is greater is its width and/or diameter. Inan embodiment, stud cap 53 includes a dimension that is greater than acorresponding dimension of stud body 51. In an embodiment, the dimensionof cap 53 that is greater is its width and/or diameter. While FIG. 9shows component 35D as having a head 39, it is within the scope of thepresent subject matter to form the FIG. 9 embodiments without head 39.

FIG. 10 shows an embodiment of the connection according to the presentinvention, which includes a plurality of components 35A. Components 35Aare each attached to a same base 45. In an embodiment, components 35A donot include a base. In an embodiment, the components 35A have the samedimensions. In an embodiment, the components 35A have differentdimensions. For example, one of the components 35A is taller than atleast one of the other components so that it extends further into thedevice assembly 10 or into the component ball 42. In an embodiment, oneof the components 35A has a width or diameter greater than at least oneof the other components. While FIG. 10 shows components 35D as having ahead 39, it is within the scope of the present invention to form theFIG. 10 embodiments without head 39.

FIG. 11 shows an embodiment of the present invention as an assembly 10that includes integrated circuit layer 12, bond pads 14, passivationlayer 16, insulating layers 21 and 25, conductive trace 23, andcomponents 35. It will be appreciated that FIG. 11 is inverted relativeto FIG. 7. To deposit connection material, such as solder paste, on thecomponents 35, the assembly 10 is positioned adjacent a componentmaterial source 70 (FIG. 12). In an embodiment, the component materialsource 70 is a molten solder bath. The assembly 10 is moved relative tosource 70 as indicated by arrow 72. The components 35 contact thecomponent material (FIG. 13). In an embodiment, components 35 are dippedinto source 70. In an embodiment, components 35 are rolled into source70. Assembly 10 is withdrawn from source 70 generally along arrow 75 inFIG. 14. Conductive material 40 from source 70 adheres to the components35. In an embodiment, material 40 encases components 35. In anembodiment, the surface of the assembly 10, namely, the surface of layer25 is coated so that material 40 does not adhere to the surface. In anembodiment, material 40 takes a generally spherical shape as thecomponents 35 are withdrawn. In an embodiment, material 40 is heated sothat it reflows into a generally spherical shape (FIG. 15).

In an embodiment, the components 35 are only partially dipped into thecollapsible material source 70. Thus, collapsible components are onlyformed at the free ends of components 35. These collapsible componentsare spaced from the surface of the integrated circuit assembly, e.g.,layer 25.

FIG. 16 shows a further method for applying conductive material 40 tothe components 35. A component material roller 80 rolls material 40 ontothe components 35. Such a rolling process is sometimes called wavesoldering. Liquid component material 40, e.g., solder, is pumped upthrough a nozzle and out the end. Gravity then causes the material tofall back down, creating a parabola shaped “wave.” The assembly 10 withcomponents 35 travels over the apex of the wave. Assembly 10 travelsrelative to the roller 80 in the direction of arrow 83. As the wave ofsolder comes in contact with the bottom side of the assembly 10, thematerial 40 bonds with the components 35. In an embodiment, thecomponents 35 include fluxed metals that chemically bond with thematerial 40. In an embodiment, roller 80 times the pulses of material 40to coincide with the passage of the components 35. In an embodiment,assembly 10 is supported by a conveyor system that moves integratedcircuit assemblies such as dies and packages. In an embodiment, theconveyor system moves the assembly 10 into a fluxing area, from thefluxing area through a preheating process, and then over the solder waveformed by solder roller 80. Wave soldering can also be used to formcollapsible component 43 on component 35. In an embodiment, the fluxingarea is not used.

FIGS. 17 and 18 show a further method for applying conductive materialto the components 35. The entire assembly 10 including components 35 isdunked into a conductive material source 90. The assembly 10 is movedgenerally in the direction of arrow 93 into source 90. In an embodiment,component 35 includes a coating. The coating retards oxides from formingon the surface of component 35. In an embodiment, the coating includes anoble metal. In an embodiment, the coating includes gold. In anembodiment, the source includes a covering of nitrogen that eliminatesthe need for a flux on the component 35. In an embodiment, the assembly10 includes a flux only on the parts of the assembly where theconductive material should adhere. In an embodiment, only the components35 include flux. Thus, the conductive material only adheres to thecomponents 35. In an embodiment, the areas on the surface of theassembly 10 closely adjacent the components 35 include flux. Theassembly 10 is withdrawn from the source 90 generally as indicated byarrow 95. Conductive material 42 adheres to the components 35.

It is within the scope of the present invention to provide a flux oncomponent 35 to assist in adhering the collapsible component 42 or 43thereto. That is, a flux is applied to the component 35 prior to orwhile applying the collapsible component 42 or 43.

FIG. 19A shows an assembly 100 that includes the integrated circuitdevice 10 of the present invention and an external circuit 101 thatincludes a further electrical contact 102. In an embodiment, theexternal circuit 101 includes a printed circuit board. In an embodiment,external circuit 101 includes a socket in an electrical device. Thecollapsible component 43 of the connection of the present invention isin its collapsed state. The collapsible component 43 is heated to softenit. Collapsible component 43 is aligned with contact 102. The externalcircuit 101 and device 10 are pressed together such that the collapsiblecomponent 43 and contact 102 press together and form a mechanical bond.In an embodiment, contact 102, collapsible component 43 and component 35form an electrical contact between circuit 101 and integrated circuitdevice 10. It will be noted that component 35 of the connection of thepresent invention does not collapse.

FIG. 19B shows an assembly 100 that includes the integrated circuitdevice 10 of the present invention and an external circuit 101 thatincludes a further electrical contact 102. The collapsible component 42of the connection of the present invention is shown in its collapsedstate. The collapsible component 42 is heated to soften it. Collapsiblecomponent 42 is aligned with contact 102. The external circuit 101 anddevice 10 are pressed together such that the collapsible member 42 andcontact 102 press together and form a mechanical bond. In an embodiment,contact 102, collapsible component 42 and component 35 form anelectrical contact between circuit 101 and integrated circuit device 10.It will be noted that component 35 of the connection of the presentinvention does not collapse.

FIG. 19A and 19B show that the embodiments of the present invention areadapted to provide a standoff space between the integrated circuitassembly 10 that includes a connect and the electrical device 100. In anembodiment, this space is filled with an underfill material. Underfillmaterial includes an epoxy resin. In an embodiment, the space is notfilled except with air. The space provides additional cooling for atleast one of the integrated circuit assembly 10 and the electronicdevice 100.

FIG. 20 shows a process according to an embodiment of the presentinvention. The process includes forming the connections 35 and 42, e.g.,first component pins and second component collapsible material, asdescribed herein. The connection(s) extends from the integrated circuitassembly. An electrical device is provided that includes a bonding sitefor the connection. In an embodiment, bond pads are formed on theelectrical device. The connection(s) are heated. In an embodiment, theentire integrated circuit assembly is heated to a temperature thatactivates the collapsible material. In an embodiment, the die is held ina collet. The collet is heated. The collet heats the die and, hence, theconnections, by conduction. The heated pin is brought into contact withthe bond site. The heated, collapsible material forms a mechanical jointwith the bond site.

In an embodiment, the connection of the present subject matter does notinclude the collapsible component. The first component 35 of theconnection is heated. For example, the first component by conductionfrom the collet to the die assembly. The heated component 35 is broughtinto contact with the bond site on the electrical device. The heatedcomponent 35 provides the energy to activate an adhesion material on thebond site. In an embodiment, the adhesion material is a collapsiblematerial. In an embodiment, the collapsible material includes a solder.

This process provides a means for creating a mechanical joint to anelectrical device that is temperature sensitive. If the electricaldevice can not be heated to a temperature that will activate theadhesive material, then the adhesive material can not create themechanical joint. Thus, the integrated circuit assembly of the presentinvention is heated to provide the needed energy to created themechanical joint. In an embodiment, the mechanical joint furtherprovides an electrical connection between the integrated circuitassembly 10 and the electrical device 100. The electrical device thathas temperature constraints includes an electromagnetic sensingintegrated circuit. The electromagnetic sensing integrated circuit, inan embodiment, is adapted to sense the visible light spectrum. Theelectromagnetic sensing integrated circuit, in an embodiment, is adaptedto sense the infrared spectrum. In an embodiment, the electrical deviceincludes a vision system. Conventional vision systems have a temperaturelimit of about 180 degrees Celsius. If the mechanical joint is createdusing a solder, then temperature at which solder typically activates,i.e., softens, to form the joint is typically greater than 180 degreesCelsius. Solder conventionally requires temperatures of greater 200degrees Celsius to activate. In an embodiment, the electrical deviceincludes a microprocessor. Convention microprocessors have a temperaturelimit of equal to or less than 200 degrees Celsius. In an embodiment,the integrated circuit assembly includes a memory device that isdirectly connected to the electrical device.

FIG. 21 shows an embodiment of a connection component 35E according tothe present invention. Component 35E is similar to the above describedcomponents except that it is formed directly on bond pad 14. In anembodiment, passivation or insulating layer 16 is formed as a continuouslayer on integrated circuit structure 12 and bond pad 14. In anembodiment, a resist layer 27A shown in broken line in FIG. 21 isdeposited on layer 16. Resist layer 27A is patterned and includes anaperture vertically aligned above bond pad 14. Layer 16 is etchedthrough the resist aperture to the bond pad 14, which acts as an etchstop. The component 35E is formed in the resist aperture and etched viain layer 16. Resist layer 27A is stripped. In an embodiment, thecomponent 35E is formed without a collapsible component thereon. Asshown in FIG. 21, a collapsible component 42A is formed on the upper endof the body 37D. Further processing and connection formation proceeds asdescribed herein and understood by one of skill in the art. For example,component 35E further includes a collapsible component as describedherein.

Integrated circuit devices having a connection assembly 35 and 42 or 35and 43 of the present invention include memory modules, device drivers,power modules, communication modems, processor modules and application-specific modules, and may include multilayer, multichip modules.Moreover, such devices may be a subcomponent of a variety of electronicsystems, such as audio systems, video systems, a clock, a television, acell phone, computers, an automobile, an industrial control system, anaircraft and others.

It will be understood that the above described embodiments could beformed with the component 35A-35E being the sole part on the integratedcircuit connection. That is, the collapsible component is not oncomponent 35A-35E. In this embodiment, the collapsible component, whichacts as a joint creating material, is on the electrical device to whichthe integrated circuit assembly is attached.

It will be further understood that an integrated circuit assembly 10, inan embodiment, includes a plurality of connection components of thepresent invention. At least a first subset of the plurality ofconnections are adapted to provide a mechanical connection between theintegrated circuit assembly 10 and the electrical device 100. At leastone of the plurality of connections provides an electrical connectionbetween the integrated circuit assembly 10 to the electrical device 100.In an embodiment, a second subset of the plurality of connectionsprovide electrical connections between the integrated circuit assembly10 to the electrical device 100.

The component 35A-35E, in an embodiment, is malleable such that is canbe stressed without failing. Failing includes breaking The component35A-35E as described herein is part of a joint, e.g., connection,between an integrated circuit assembly 10 and an electrical device 100.The assembly 10 and device 100 have different coefficients of thermalexpansion, which causes the assembly and device to move relative to oneanother based on the operating environment. The component 35A-35E isadapted to yield to this relative movement while maintaining thestructural and electrical integrity of the connection formed at least inpart by the component 35A-35E.

Conclusion

The connections of the present invention provide an economicallyfeasible structure and method that produces small device connectionsthat have sufficient strength. The size of device connections continueto shrink as chip sizes shrink and the number of contacts rises. Thepresent invention includes connections that are smaller than 100microns. However, continued reduction of device connections such assolder balls or bumps increases the likelihood that the deviceconnections will fail. One aspect of the failure is the reduction inmaterial which in turn reduces the area that adheres to the devicesurface (wetable surface). This reduces shear strength. The presentinvention provides a connection that improve adhesion of the deviceconnection to the device assembly and improves shear strength. Thepresent invention addresses these problems and provides an improvementin the art by providing a multi-component contact. In an embodiment, afirst component of the connection is in the shape of a spike or nailthat assists in securing the second, collapsible component (e.g., solderbump) to the surface. In the present invention, the shear value dependson both the connection material and the first component. In anembodiment, the first component is formed of a high shear strengthmaterial. For example, the first component is a metal pin. As a result,the device connection has a shear strength that is higher than thecollapsible, connection material alone. Moreover, the formation of thefirst component and application of the connection material to thecomponent does not require a large, expensive investment in equipment.Further, the connection material (solder) will have a limited collapseas the component (spike) acts as an upright to support the connectionmaterial during its joining to another structure. Still further, thefirst component inhibits crack propagation in the connection material ineither its formation or during it connection to another structure.

The present invention is directed to an integrated circuit contact andits method of manufacture. An embodiment of the present inventionincludes a multi-component integrated circuit contact. The contactincludes a first component and a second component that provides amechanical connection to another device. In an embodiment, the secondcomponent includes a collapsible component. The collapsible component isadapted to form a mechanical connection with another contact. In anembodiment, the collapsible component forms an electrical connection. Inan embodiment, the first component is elongate and has a first portionand a second portion that is adapted to be fixed to an integratedcircuit structure. In an embodiment, the first portion includes a neckand a head on the neck. The head has a dimension that is greater than adimension of the neck. In an embodiment, the dimensions are width. In anembodiment, the collapsible component includes solder. In an embodiment,first component includes a metal. In an embodiment, the first componentincludes nickel. In an embodiment, the first component includes copper.An embodiment includes a plurality of first components connected to onecollapsible component. An embodiment includes a base within theintegrated circuit structure connected to the first component.

An embodiment of the present invention includes an integrated circuitthat has a bond pad connected to a trace. The first component extendsinto layers covering the integrated circuit to contact the trace. In anembodiment, a redistribution level covers the integrated circuit. In anembodiment, a passivation layer covers the integrated circuit.

The present invention also includes methods for creating a contactaccording to the present invention. In an embodiment, the methodincludes forming a first component that is fixed to an integratedcircuit structure and extends above the integrated circuit structure. Asecond, collapsible component is fixed to the exposed portion of thefirst component. In an embodiment, the collapsible component is joinedto another contact to form a mechanical and/or an electrical connection.An embodiment of the present invention includes providing an integratedcircuit structure, forming a redistribution level on the integratedcircuit structure, forming a first electrical connection componentincluding a first portion extending from the redistribution level, andforming a second electrical connection component on the first portion.In an embodiment, the integrated circuit structure includes a bond pad.In an embodiment, a passivation layer covers the integrated circuitstructure except over at least part of the bond pad. In an embodiment, atrace connects to the bond and the first component.

A further embodiment of the method according to the present inventionincludes forming a recess in the non-conductive layer of the integratedcircuit structure, depositing a conductive material in the recess suchthat at least a portion of the conductive material extends above thenon-conductive layer, and forming a collapsible material on the portionof the conductive material. In an embodiment, forming the recess in thenon-conductive layer includes placing a resist layer on thenon-conductive layer. In an embodiment, placing the resist layerincludes forming an aperture in the resist layer. In an embodiment,forming a recess in the non-conductive layer includes etching throughthe aperture to form a via in the non-conductive layer to a conductorthat is connected to an integrated circuit. In an embodiment, depositinga conductive material in the recess includes placing a conductivematerial in the aperture and the via. In an embodiment, placing theconductive material includes plating a metal in the aperture and thevia. In an embodiment, depositing a conductive material includesremoving the resist layer such that the portion of the conductivematerial extends above the integrated circuit structure. In anembodiment, forming a collapsible material on the portion of theconductive material includes placing a solder on the portion of theconductive material. In an embodiment, forming a collapsible material onthe portion of the conductive material includes dipping the portion ofthe conductive material in a collapsible material bath. In anembodiment, forming a collapsible material on the portion of theconductive material includes rolling the portion of the conductivematerial in a collapsible material bath. In an embodiment, forming acollapsible material on the portion of the conductive material includesusing a solder wave to place the collapsible material on the portion ofthe conductive material. In an embodiment, forming a collapsiblematerial on the portion of the conductive material includes dunking theentire portion of the conductive material and the integrated circuitstructure in a bath of collapsible material.

The present invention also includes substrates, wafers, integratedcircuit packages, electrical devices, memory units, memory modules,electrical systems, computers, which include a contact according to thepresent invention.

These and other embodiments, aspects, advantages, and features of thepresent invention will be set forth in part in the description, and inpart will become apparent to those skilled in the art by reference tothe description and referenced drawings or by practice of the invention.The aspects, advantages, and features of the invention are realized andattained by means of the instrumentalities, procedures, and combinationsparticularly pointed out in the appended claims.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement which is calculated to achieve the same purpose maybe substituted for the specific embodiments shown. Adaptations of theinvention will be apparent to those of ordinary skill in the art.Accordingly, this application is intended to cover any adaptations orvariations of the invention. It is manifestly intended that thisinvention be limited only by the following claims and equivalentsthereof.

1. An integrated circuit connection assembly comprising: an elongatefirst conductor including a first portion and a second portion, thesecond portion configured to be attached to an integrated circuitstructure; an elongate second conductor including a third portion and afourth portion, the fourth portion configured to be attached to theintegrated circuit structure; and a third conductor, wherein the firstportion of the first conductor and the third portion of the secondconductor extend into the third conductor in a first direction.
 2. Theintegrated circuit connection assembly of claim 1, wherein the firstconductor includes a first end and a head on the first end, wherein thesecond conductor includes a second end and a head on the second end, andwherein the heads of the first and second conductors extend within thethird conductor in a second direction substantially perpendicular to thefirst direction.
 3. The integrated circuit connection assembly of claim2, wherein the second portion includes a third end and the fourthportion includes a fourth end, wherein the third end is attached to abase and the fourth end is attached to the base, the base extendingwithin the integrated circuit structure in a third directionsubstantially perpendicular to the first direction.
 4. The integratedcircuit connection assembly of claim 3, wherein the elongate firstconductor, the elongate second conductor, and the base are formed of asame material.
 5. The integrated circuit connection assembly of claim 2,wherein the head on the first end has a different diameter than the headon the second end.
 6. The integrated circuit connection assembly ofclaim 1, wherein the first conductor is longer than the secondconductor.
 7. The integrated circuit connection assembly of claim 1,wherein the third conductor includes solder and the first and secondconductors include one or more materials having a higher shear strengththan the third conductor.
 8. The integrated circuit connection assemblyof claim 1, wherein the third conductor includes a solder ball.
 9. Anintegrated circuit connection assembly comprising: a base in anintegrated circuit structure; an elongate first conductor including afirst portion and a second portion, the second portion being attached tothe base; an elongate second conductor including a third portion and afourth portion, the fourth portion being attached to the base; and athird conductor, wherein the first portion of the first conductor andthe third portion of the second conductor extend into the thirdconductor in a first direction.
 10. The integrated circuit connectionassembly of claim 9, wherein the first conductor includes a longitudinalfirst axis, the first portion of the first conductor including a firstsurface extending substantially radially outwardly from the first axisto an outer edge of the first surface, the first portion including arounded second surface remote from the second portion and extending fromthe outer edge of the first surface to approximately a center of thesecond surface along the first axis.
 11. The integrated circuitconnection assembly of claim 10, wherein the first axis extends in thefirst direction.
 12. The integrated circuit connection assembly of claim10, wherein the second conductor includes a longitudinal second axis,the third portion of the second conductor including a first surfaceextending substantially radially outwardly from the second axis to anouter edge of the first surface, the third portion including a roundedsecond surface remote from the fourth portion and extending from theouter edge of the first surface to approximately a center of the secondsurface along the second axis.
 13. The integrated circuit connectionassembly of claim 12, wherein the first axis is substantially parallelto the second axis.
 14. The integrated circuit connection assembly ofclaim 9, wherein the first conductor is a different length than thesecond conductor.
 15. The integrated circuit connection assembly ofclaim 9, wherein the third conductor includes a collapsible material.16. The integrated circuit connection assembly of claim 9, wherein thefirst and second conductors each include a rigid body.
 17. An integratedcircuit connection assembly comprising: an elongate first conductorincluding a first portion and a second portion, the second portionconfigured to be attached to an integrated circuit structure, the firstconductor including a longitudinal first axis, the first conductorincluding a first end, the first end including a head extending radiallyoutwardly from the first axis; an elongate second conductor including athird portion and a fourth portion, the fourth portion configured to beattached to the integrated circuit structure, the second conductorincluding a longitudinal second axis, the second conductor including asecond end, the second end including a head extending radially outwardlyfrom the second axis; and a third conductor, wherein the first portionof the first conductor and the third portion of the second conductorextend into the third conductor along the first and second axes,respectively.
 18. The integrated circuit connection assembly of claim17, wherein the heads of the first and second conductors each include: afirst surface extending substantially radially outwardly from the firstaxis or the second axis to an outer edge of the first surface; and arounded second surface extending from the outer edge of the firstsurface to a center of the second surface along the first axis or thesecond axis.
 19. The integrated circuit connection assembly of claim 17,wherein the head of the first end is differently sized from the head ofthe second end.
 20. The integrated circuit connection assembly of claim17, comprising a base extending within the integrated circuit structurein a direction substantially perpendicular to the first and second axes,wherein the second portion of the first conductor includes a third endand the fourth portion of the second conductor includes a fourth end,wherein the third end and the fourth end are attached to the base.